CVE-2026-15534 Affecting perl package, versions <5.30.0-9ubuntu0.5+esm4


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.16% (6th percentile)

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  • Snyk IDSNYK-UBUNTU2004-PERL-18741414
  • published9 Sept 2026
  • disclosed9 Aug 2026

Introduced: 9 Aug 2026

NewCVE-2026-15534  (opens in a new tab)

How to fix?

Upgrade Ubuntu:20.04 perl to version 5.30.0-9ubuntu0.5+esm4 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream perl package and not the perl package as distributed by Ubuntu. See How to fix? for Ubuntu:20.04 relevant fixed versions and status.

Perl versions through 5.45.1 have out-of-bounds heap reads and writes during regular expression matching via an undersized superlinear cache in S_regmatch.

The regex engine's superlinear cache holds one bit per subject position for each participating WHILEM node, so the bit count is the subject length plus one times the number of nodes. Nothing checks that product for positive overflow of the signed 32-bit count: a 286331153 byte subject matched against a pattern with 15 participating nodes stores the count as 14, leaving a two byte cache. The cache is then indexed from the real match position and node number, so reads go past the end of the allocation, and on failure CACHEsayNO sets a bit past it.

A caller that matches an attacker controlled subject of this size against a pattern of this shape can crash the process or corrupt heap memory.

CVSS Base Scores

version 3.1